1. Field of the Invention
The present invention relates to a mobile telephone, and more particularly to a method for switching a mobile telephone for selectively transmitting or receiving a voice signal.
2. Description of the Related Art
Recently, a more compact sized mobile telephone, such as the folder-type mobile telephone, has been developed. These newer mobile telephones incorporate an additional function of a speakerphone mode that enables the user to conduct a voice communication without holding the mobile telephone by his ear. However, the conventional mobile telephone with such an additional function inherently suffers particular drawbacks. One of these drawbacks is that the received voice signal emanating from a speaker may unintentionally feedback through the microphone to the sender, thus causing unwanted interference. This interference, or garble, is known as a howling phenomenon. Moreover, the mobile telephone only operates in either a receive mode or transmit mode at any point in time based on the voice signal (i.e. the transmitted voice signal or the received voice signal) with the greater intensity. This limitation creates a problem in that the user cannot be assured that his voice signal input through the microphone is being transmitted to the other user. The present invention solves this longstanding problem in the present technology.
It is an object of the present invention to provide a method for switching a mobile telephone for selectively receiving or transmitting a voice signal in the speakerphone mode so as to prevent the howling phenomenon.
According to one embodiment of the present invention, a method for switching the mobile telephone for selectively receiving or transmitting a voice signal in the speakerphone mode, comprises the steps of counting the number of the full-rate voice data received from the sender, and blocking the transmission path from the receiver to prevent the received voice data from being retransmitted back through the microphone of the receiver to the sender if the number of the full-rate voice data exceeds a predetermined value.